The present invention relates to the field of well completion assemblies for use in a wellbore. More particularly, the invention provides a method and apparatus for completing and producing from multiple mineral production zones, independently or in any combination.
The need to drain multiple-zone reservoirs with marginal economics using a single well bore has driven new downhole tool technology. While many reservoirs have excellent production potential, they cannot support the economic burden of an expensive deepwater infrastructure. Operators needed to drill, complete and tieback subsea completions to central production facilities and remotely monitor, produce and manage the drainage of multiple horizons. This requires rig mobilization (with its associated costs running into millions of dollars) to shut off or prepare to produce additional zones from the central production facility.
Another problem with existing technology is its inability to complete two or more zones in a single well while addressing fluid loss control to the upper zone when running the well completion hardware. In the past, expensive and often undependable chemical fluid loss pills were spotted to control fluid losses into the reservoir after perforating and/or sand control treatments. A concern with this method when completing upper zones is the inability to effectively remove these pills, negatively affecting the formation and production potential and reducing production efficiency. Still another problem is economically completing and producing from different production zones at different stages in a process, and in differing combinations. The existing technology dictates an inflexible order of process steps for completion and production.
Prior systems required the use of a service string, wire line, coil tubing, or other implement to control the configuration of isolation valves. Utilization of such systems involves positioning of tools down-hole. Certain disadvantages have been identified with the systems of the prior art. For example, prior conventional isolation systems have had to be installed after the gravel pack, thus requiring greater time and extra trips to install the isolation assemblies. Also, prior systems have involved the use of fluid loss control pills after gravel pack installation, and have required the use of through-tubing perforation or mechanical opening of a wireline sliding sleeve to access alternate or primary producing zones. In addition, the installation of prior systems within the wellbore require more time consuming methods with less flexibility and reliability than a system which is installed at the surface. Each trip into the wellbore adds additional expense to the well owner and increases the possibility that tools may become lost in the wellbore requiring still further operations for their retrieval.
While pressure actuated valves have been used in certain situations, disadvantages have been identified with such devices. For example, prior pressure actuated valves had only a closed position and an open position. Thus, systems could not reliably use more than one such valve, since the pressure differential utilized to shift the first valve from the closed position to the open would be lost once the first valve was opened. Therefore, there could be no assurance all valves in a system would open.
There has therefore remained a need for an isolation system for well control purposes and for wellbore fluid loss control, which combines simplicity, reliability, safety and economy, while also affording flexibility in use.
The present invention provides a system which allows an operator to, perforate, complete, and produce multiple production zones from a single well in a variety of ways allowing flexibility in the order of operation. An isolation system of the present invention does not require tools to shift the valve and allows the use of multiple pressure actuated valves in a production assembly.
According to one aspect of the invention, after a zone is completed, total mechanical fluid loss is maintained and the pressure-actuated circulating (PAC) and/or pressure-actuated device (PAD) valves are opened with pressure from the surface when ready for production. This eliminates the need to rely on damaging and sometimes non-reliable fluid loss pills being spotted in order to control fluid loss after the frac or gravel pack on an upper zone (during the extended time process of installing completion production hardware).
According to another aspect of the present invention, the economical and reliable exploitation of deepwater production horizons that were previously not feasible are within operational limits of a system of the invention.
A further aspect of the invention provides an isolation sleeve assembly which may be installed inside a production screen and thereafter controlled by generating a pressure differential between the valve interior and exterior.
According to a still another aspect of the invention, there is provided a string for completing a well, the string comprising: a base pipe comprising a hole; at least one packer in mechanical communication with the base pipe; at least one screen in mechanical communication with the base pipe, wherein the at least one screen is proximate the hole in the base pipe; an isolation pipe concentric within the base pipe and proximate to the hole in the base pipe, wherein an annulus is defined between the base pipe and the isolation pipe; and an annulus-to-annulus valve in mechanical communication with the base pipe and the isolation pipe.
Another aspect of the invention provides a system for completing a well, the system comprising: a first string comprising: a first base pipe comprising a hole, at least one first packer in mechanical communication with the first base pipe, at least one first screen in mechanical communication with the first base pipe, wherein the at least one first screen is proximate the hole in the first base pipe, a first isolation pipe concentric within the first base pipe and proximate to the hole in the first base pipe, wherein a first annulus is defined between the first base pipe and the first isolation pipe, and a first annulus-to-annulus valve in mechanical communication with the first base pipe and the first isolation pipe; and a second string which is stingable into the first string, the second string comprising: a second base pipe comprising a hole, at least one second screen in mechanical communication with the second base pipe, wherein the at least one second screen is proximate the hole in the second base pipe, a second isolation pipe concentric within the second base pipe and proximate to the hole in the second base pipe, wherein a second annulus is defined between the second base pipe and the second isolation pipe, and a second annulus-to-annulus valve in mechanical communication with the second base pipe and the second isolation pipe.
According to an aspect of the invention, there is provided a system for completing a well, the system comprising: a first string comprising: a first base pipe comprising a hole, at least one first packer in mechanical communication with the first base pipe, at least one first screen in mechanical communication with the first base pipe, wherein the at least one first screen is proximate the hole in the first base pipe, a first isolation pipe concentric within the first base pipe and proximate to the hole in the first base pipe, wherein a first annulus is defined between the first base pipe and the first isolation pipe, and a first annulus-to-annulus valve in mechanical communication with the first base pipe and the first isolation pipe; and a second string which is stingable into the first string, the second string comprising: a second base pipe comprising a hole, at least one second screen in mechanical communication with the second base pipe, wherein the at least one second screen is proximate the hole in the second base pipe, a second isolation pipe concentric within the second base pipe and proximate to the hole in the second base pipe, wherein a second annulus is defined between the second base pipe and the second isolation pipe, and a second annulus-to-annulus valve in mechanical communication with the second base pipe and the second isolation pipe; and a third string which is stingable into the second string, the third string comprising: a third base pipe comprising a hole, at least one third screen in mechanical communication with the third base pipe, wherein the at least one third screen is proximate the hole in the third base pipe, a third isolation pipe concentric within the third base pipe and proximate to the hole in the third base pipe, wherein a third annulus is defined between the third base pipe and the third isolation pipe, and a third annulus-to-annulus valve in mechanical communication with the third base pipe and the third isolation pipe.
According to a further aspect of the invention, there is provided a method for completing multiple zones, the method comprising: setting a first string in a well proximate a first production zone, wherein the first string comprises: a first base pipe comprising a hole, at least one first packer in mechanical communication with the first base pipe, at least one first screen in mechanical communication with the first base pipe, wherein the at least one first screen is proximate the hole in the first base pipe, a first isolation pipe concentric within the first base pipe and proximate to the hole in the first base pipe, wherein a first annulus is defined between the first base pipe and the first isolation pipe, and a first annulus-to-annulus valve in mechanical communication with the first base pipe and the first isolation pipe; performing at least one completion operation through the first string; isolating the first production zone with the first string; and producing fluids from the first production zone.
According to a further aspect of the invention, there is provided a method for completing multiple zones, the method comprising: setting a first string in a well proximate a first production zone, wherein the first string comprises: a first base pipe comprising a hole, at least one first packer in mechanical communication with the first base pipe, at least one first screen in mechanical communication with the first base pipe, wherein the at least one first screen is proximate the hole in the first base pipe, a first isolation pipe concentric within the first base pipe and proximate to the hole in the first base pipe, wherein a first annulus is defined between the first base pipe and the first isolation pipe, and a first annulus-to-annulus valve in mechanical communication with the first base pipe and the first isolation pipe; performing at least one completion operation through the first string; isolating the first production zone with the first string; and producing fluids from the first production zone; stinging a second string into the first string and setting the second string proximate a second production zone, wherein the second string comprises: a second base pipe comprising a hole, at least one second screen in mechanical communication with the second base pipe, wherein the at least one second screen is proximate the hole in the second base pipe, a second isolation pipe concentric within the second base pipe and proximate to the hole in the second base pipe, wherein a second annulus is defined between the second base pipe and the second isolation pipe, and a second annulus-to-annulus valve in mechanical communication with the second base pipe and the second isolation pipe; performing at least one completion operation through the second string; and producing fluids from the second production zone through the second string.